linux-kernel - Re: [PATCH 2 of 4] [x86-64] Calgary: only verify the allocation bitmap if CONFIG_IOMMU

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Message-ID: <20060803071935.GB4736@rhun.haifa.ibm.com>
Date:	Thu, 3 Aug 2006 10:19:35 +0300
From:	Muli Ben-Yehuda <muli@...ibm.com>
To:	Jon Mason <jdmason@...ibm.com>
Cc:	ak@...e.de, linux-kernel@...r.kernel.org, discuss@...-64.org
Subject: Re: [PATCH 2 of 4] [x86-64] Calgary: only verify the allocation bitmap if CONFIG_IOMMU_DEBUG is on

On Wed, Aug 02, 2006 at 10:57:24PM -0500, Jon Mason wrote:

> > diff -r 9cd758467ce1 -r 515131a26b15 arch/x86_64/kernel/pci-calgary.c
> > --- a/arch/x86_64/kernel/pci-calgary.c	Thu Aug 03 01:37:12 2006 +0300
> > +++ b/arch/x86_64/kernel/pci-calgary.c	Thu Aug 03 01:40:21 2006 +0300
> > @@ -133,12 +133,35 @@ static inline void tce_cache_blast_stres
> >  {
> >  	tce_cache_blast(tbl);
> >  }
> > +
> > +static inline unsigned long verify_bit_range(unsigned long* bitmap,
> > +	int expected, unsigned long start, unsigned long end)
> > +{
> > +	unsigned long idx = start;
> > +
> > +	BUG_ON(start > end);
> 
> This should be ">=".

I considered both options and decided that since this is debug code,
we might as well be permissive and not trip when start == end (because
I'm not 100% sure we never do it). However since it could arguably be
masking a real bug if we do, I agree with the change.

Cheers,
Muli
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